CELLULAR IMAGING CORE (CORE C) ABSTRACT The research efforts of IDDRC investigators at Boston Children's Hospital and Harvard Medical School have increasingly come to rely on high-end and expensive microscopy and digital imaging approaches. Understanding the underlying mechanisms and structural changes associated with neurodevelopmental disorders require that researchers visualize the morphological and cell signaling events in fixed tissue and in intact network of cells in situ, such as in in vitro organ explants and in vivo awake behaving organisms. The IDDRC Cellular Imaging Core furthers research and advancement of knowledge by lowering barriers to entry for state-of-the-art light microscopy. Our specific aims are: 1) To provide affordable access to high-end microscopy instruments and image analysis workstations. 2) To provide training, consultation and education to IDDRC researchers, and 3) To identify and obtain new equipment and technology that is relevant to the research of IDDRC investigators. The core offers multiphoton, confocal and widefield microscopes as well as image analysis workstations and software that are widely used by IDDRC investigators. Over the past grant period, 32 IDDRC labs have used the core an average of 9,187 hours/year. During this period, the core expanded its capacity and capabilities by raising $1.4 million in outside funding for the purchase of new instrumentation, including a $500,000 NIH shared instrumentation grant for a multiphon/confocal. IDDRC investigators have used the core to investigate and advance our understanding of normal and pathological neural development, plasticity, and function. The goal of the Boston Children's Hospital IDDRC Cellular Imaging Core for this next funding period is to continue to provide IDDRC investigators with affordable access to state-of-the-art equipment, services, training and advice for projects using light microscopy. In fulfilling this goal, the core helps to insure that instrument cost or technical complexity will not slow or thwart research into intellectual disabilities and developmental disorders.